Persons afflicted with incontinence (i.e., the inability of a person intentionally to retain and void urinary fluid) experience greatly impaired normal life functions and substantial psychological stress. Substantial effort has therefore been made to fashion technical devices to assist persons afflicted with incontinence, such a absorbing devices (e.g., absorbent pads worn externally over the patient's urethra orifice), external collection systems and internally placed urinary fluid drainage systems.
A closure or damming device for male urethras has been proposed in DE-OS 19 57 693 which is formed from a short, slender, elastic tube of soft rubber closed at its posterior end and open and its anterior end. The interior of the tube is provided with a holding device that is placed into the tube's open anterior end and is connected securely to the tube. The holding device is operated by means of a head part which projects beyond the anterior end of the tube. That is, by turning a screw placed in the head part, and with the help of a number of spreader levers, the tube is stretched far enough so the closure device is held firmly in the urethra sufficiently to effect urethral closure.
The device disclosed in DE-OS 19 57 693 has several disadvantages. For example, it is not leak-proof. When the tube is stretched, the spreader levers form a polygon such that two parallel surfaces that cannot be leak-proof are formed between the bearing points. To make such surfaces leak-proof, therefore, the elastic forces would have to be infinitely great. Furthermore, the head part disadvantageously projects beyond the external orifice of the urethra and consequently is disruptive to wear--that is, on the one hand, the weight of the head part affects and hurts the urethra and its surrounding tissue, while on the other hand, pain is caused by friction (e.g., with the penis and glans).
What has been needed in this art therefore, is a device for controlling incontinence which is "user-friendly". That is, what has been needed is an economical and environmentally safe incontinence control device which allows the user to insert/remove the device without external medical assistance; is lightweight so as to promote optimal comfort when inserted; and ensures that a secure and absolutely leak-proof damming effect of the urethra is achieved. It is towards fulfilling such needs that the present invention is directed.
Broadly, the present invention is embodied in a urethral damming device which has a closed anterior end and an open posterior end. The device most preferably includes a unitary body formed of a flexible, resilient biocompatible material which has an interiorly recessed hollow cavity extending from the open posterior end lengthwise towards the closed anterior end. The device of this invention therefore does not have any separately installed components which could affect its weight and wearing comfort.
The recessed hollow cavity most preferably defines the generatrices of an elliptical parabolic surface, but could perform equivalent functions if it was formed into a generally cylindrical or conical shape. The device is sufficiently elongate to allow its external surface to press sealingly against the urethral tissue, but not extending longer than the urethral tract. As a result, the device of this invention can satisfactorily be used in the male urethral anatomy.
In preferred forms, the device of this invention will have a flexible recovery element (e.g., a length of thread) attached to the closed anterior end of the device and adapted to extend externally of the urethra orifice. As a result, the user may simply pull on the flexible recovery element so as to remove the device from its position within that person's urethra.
The device of this invention is preferably configured so as to have an approximate geometric shape corresponding to an elliptical paraboloid. However, the device can also be configured in other geometric shapes, such as approximately cylindrical or conical. The maximum length of the device is the length of the male patient's urethra in which the device will be placed. However, in practice, the length of the device is substantially shorter than the length of the male patient's urethra, for example, between about 2 to about 5 cm.
The device is placed in the patient's urethra so that its closed anterior end lies fiat against, but does not extend beyond, the exterior urethral orifice (e.g., posteriorly of the meatus urinarius). The device is preferably formed as a unitary body of a flexible, resilient, biocompatible material (e.g., silicone rubber). The hollow interior recessed cavity most preferably has a wall thickness which is greater in the region of the closed anterior end and gradually tapers toward the open posterior end. With such an arrangement, it has been found that the device of the present invention may be securely seated within the patient's urethra so that it lies against the urethral walls to form a leak-proof seal therewith.
Presumably, the leak-proof seal established by the device of this invention can be attributed to the pressure in the bladder which is transferred by the urinary fluid column within the urethra to the interior of the device. This transferred pressure is therefore believed to elastically expand the flexible wall which annularly surrounds and defines the recessed hollow cavity in the device of this invention thereby causing the walls to press sealingly against the urethral tissue. The contact pressure therefore presumably changes in proportion of the pressure transferred by the urinary fluid column within the urethra. As a result, increasing pressure exerted by the urinary fluid within the recessed hollow cavity will translate into increased contact pressure between the urethra tissue and the external surfaces of the device. Since the device is formed from a flexible material, the exterior surfaces of the device will conform to irregularities of the urethra tissue. The device of this invention may also be prestressed so that the wall which annularly surrounds the interior recessed cavity is inherently biased to expand within the urethra and thereby ensure a leak-proof seal even in the absence of a urinary fluid column.
Further aspects and advantages of this invention will become more clear after careful consideration is given to the following detailed description of the preferred exemplary embodiment.